Do We Need CAD during Conceptual Design

This paper presents the results of experiments to test whether a designer necessarily needs to produce and utilize external representations in the very early phases of conceptual design. Three architects are engaged in two separate design processes, one is the experiment condition where they were not allowed sketch, and the other, the control condition where they were allowed to sketch. In the experiment condition, architects were required to put on a blindfold and think aloud while designing. The results show that in both conditions the design outcomes fit in the given dimensions of the site, accommodate the space requirements and allow an effective use for the clients. Thus, when the participants were blindfolded, they were able to produce designs by using their cognitive resources to create and hold an internal representation of the design rather than by sketching, or using a CAD tool. We finally raise the question: do architects need CAD representations during the conceptual phase of the design activity?